Biosensors are devices that typically use biological molecules to detect other biological molecules or chemical substances.
Specific and/or selective binding interactions with one or more biomolecules (“ligands”) such as peptides, proteins, enzymes, antibodies, receptors, nucleic acids, aptamers, or the like detect one or more target molecules (“analytes”). Binding of the target molecule to the ligand results in a signal that can be used to detect or quantify the analyte present in a sample. The detector molecules are connected in some way to a sensor that can be monitored by a computer or similar mechanism. Biosensors may use a monoclonal antibody to detect an antigen, or a small synthetic DNA molecule called an oligodeoxyribo-nucleotide to detect DNA.
There is a critical demand for a rapid, simple, cost-effective technique for screening samples, such as blood or other clinical samples, for the presence of biomolecules, including polynucleotides, polypeptides, etc. Specifically, the detection of cells, viruses, spores, antibodies, pathogens, or other proteins is considered important in diagnosing and treating diseases. Such detection is also useful for detecting and quantifying such molecules in pathological and forensic samples.
A wide variety of biosensors of different designs is known to those of skill in the art. Such biosensors are designed for use in clinical research laboratories or similar facilities, but tend to be very bulky, expensive, and relatively fragile. Such biosensor systems are typically complex and require highly trained operators to obtain accurate analysis results. Portable biosensor systems based on immunoassays using the optical waveguide as a platform have become an attractive area in sensor research due to the availability of a wide variety of low cost, low power consuming components and bright photostable fluorophores.